Rotor for rotary-piston mechanism

ABSTRACT

In a rotary piston mechanism of the Wankel type the rotor has an improved bearing means for limiting the lateral movement of the piston between the end walls of the mechanism housing. This improved bearing means comprises a plurality of wear members each of which is formed by spraying a powdered material having selflubricating and wear-resisting characteristics in a shallow recess or pocket formed by a rim or bead projecting from the end face of the rotor.

United States Patent 1191 Ruf 'Nov. 13, 197-3 [5 ROTOR FOR ROTARY-PISTON 3,289,649 12/1966 Lamm 418/179 x MECHANISM 3,401,872 9/1968 Adsit 418/179 x 3,456,624 7/1969 Okamoto 418/142 [75] Inventor: Max Ruf, Obereisesheim, Germany [73] Assignees: Aude Nsu Auto Union Aktiengesellschaft, Neckarsulum; Primary Examiner-Carlton R. Croyle Wankel GmbH, Lindau, Bo d Assistant Examiner-Richard Sher b h of Germany Atl0rneyArthur Frederick et a1.

[22] Filed: Mar. 8, 1972 [21] App]. No.: 232,702

. [57] ABSTRACT [30] Foreign Application Priority Data Mar. 16, 1971 Germany"; P 21 12 615.8 In a rotary Piston mechanism of the Wankel yp the rotor has an improved bearing means for limiting the 52 U.S. c1 418/61, 308/239, 418/178, lateral movement of the p t between the n walls 413/179 of the mechanism housing. This improved bearing [51] Int. Cl. F0lc 1/02 means pr s a p li y f w ar members each of [58] Field of Search 418/179, 142, 178, which is formed y p y a Powdered material 418/61; 303/239 ing self-lubricating and wear-resisting characteristics in a shallow recess or pocket formed by a rim or bead [56] Refere Cit d projecting from the end face of the rotor.

UNITED STATES PATENTS 12/1970 Belzner 418/179 6 Claims, 2 Drawing Figures 1 ROTOR FOR ROTARY-PISTON MECHANISM DISCLOSURE OF THE INVENTION This invention relates to rotary piston mechanisms of the type disclosed in the U. S. Pat. to Wankel et al., No. 2,988,065, and more particularly, to the end face bearing means for axially positioning the rotors of such rotary piston mechanisms.

BACKGROUND OF THE INVENTION In rotary piston mechanisms of the type disclosed in the aforesaid patent, a rotor, having substantially plane end surfaces or faces extending perpendicular to the axis of rotation, is supported for rotation eccentrically between two substantially planar, parallel end walls of an outer casing or housing. In addition to seal rings and/or bars interposed between the end faces and the adjacent housing end wall surface to seal the interstices between those adjacent surfaces, bearing means are provided to maintain the rotor in axial position relative to the housing end wall surfaces. Heretofore, various bearing means have been devised to axially position the rotary piston for rotation in a housing or casing, some of these bearing means are disclosed in the following U. S. Pats:

Baumler et al. No. 3,193,052

Jones No. 3,261,542

Belzner No. 3,545,901

overcome by the present invention'in which accurate machining is eliminated;

It is, therefore, an object of this invention to provide an improved end face bearing means for the rotor of a rotary piston mechanism which is easy and inexpensive to fabricate.

Another object of the present invention is to provide an improved end face bearing means for the rotor of a rotary piston mechanism in which relatively accurate machining is obviated.

SUMMARY OF THE INVENTION Accordingly, it is contemplated by this invention to provide a rotor for a rotary piston mechanism with novel end face bearing means for limiting axial movement of the rotor relative to the housing end walls of the mechanism. The bearing means comprises, in each end face of the rotor, a plurality of spaced bearing members projecting in a plane beyond the plane of the associated end face surface of the rotor and in engagement with the end walls of the housing. Each of the bearing members consists of a recess or pocket defined by a rim or flange projecting from the plane of the end face surface of the rotor and a powderedmaterial having self-lubricating and high resistance to wear characteristics is sprayed into the recess. The spraying may be accomplished by any suitable apparatus and method well known to those skilled in the metal coating art, such as high velocity plasma spraying or the like.

It is preferred for a rotary piston constructed of light metal alloy that each bearing member according to this invention be constructed of molybdenum sprayed'into the recess formed by a rim or flange.'Whilemolybdenum bonds strongly to the rotary piston surface, it is relatively brittle and the rim or flange of rotary piston material, or other material of greater tensile strength, protects the molybdenum layer from fracture and crumbling. I

BRIEF DESCRIPTION OF THE DRAWING The invention will be more fully understood from the following detailed description thereof when considered in connection with the accompanying drawings wherein one embodiment of the invention is shown by way of example, and in which:

FIG. 1 is a fragmentary cross-sectional view of a rotary piston mechanism showing'in elevation one of the apex portions of the rotary piston according to this invention; and

FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1. I

DESCRIPTION OF THE PREFERRED EMBODIMENT Now referring to the drawings, the reference number 10 generally designates a rotary piston or rotor for a rotary piston mechanism of the type disclosed-in the U. S. Patent to Wankel et al., No. 2,988,065. The rotor 10 is supported for eccentric rotation in a cavity 12 formed within a housing comprising two end walls 14 (only one of which is shown in FIG. 2) spaced apart by an intermediate wall 16 having a generated peripheral surface 17 which may be of the epitrochoidal shape.

The rotor 10 comprises a generally triangular shaped body having opposite end faices 18 and a plurality of peripheral surfaces 19 (only two of which are partially shown in FIG. 1) which converge to form a-plurality of apex portions 20 (only one of which is shown). An apex seal 21 is mounted in each apex portion 20 to engage peripheral surface l7 of the housing insealing contact with that surface. As is conventional, the rotor also carries on each end face'18 a'plurality of seal strips 22 and seal pins 24 disposed between the seal strips and apex seal 21. The seal strips 22 and seal pins are constructed and arranged to slidably and resiliently engage the adjacent surface 26 of end walls 14, and thus effect a gas seal. To limit axial movement of rotor 10 within housing cavity 12 and relative to housing end walls 14, bearing members 30 are provided in each end face 18 of rotor 10 to protrude from the end faces and abut adjacent surfaces 26 of end walls 14.

In accordance with the present invention, each wear 1 plasma and detonation guns are employed to apply the material. The rim may be cast or machined in the end faces of rotor and, while the rim is shown as circular in shape, it may be of any other geometric configuration without departure from the scope and spirit of this invention. The rim 32 functions to protect the peripheral edge of the sprayed layer 36 against crumbling when such layer 36 is of a material, such as molybdenum, which is brittle. By preventing the fracture and the crumbling of the sprayed layer 36 under lateral stresses, the surfaces of the end faces of the rotor and surfaces 26 of the housing end walls 14 are protected against scoring which would otherwise occur from the disintegrated particles.

It is believed now readily apparent that the present invention provides in a rotary-piston mechanism of the trochoidal type, a rotor having an improved bearing means for limiting axial movement of the rotor, which bearing means is relatively easily and inexpensively produced since accurate machining is unnecessary.

Although but one embodiment of the invention has been illustrated and described in detail, it is to be expressly understood that the invention is not limited thereto. Various changes can be made in the arrangement of parts without departing from the scope and spirit of the invention as the same will be understood by those skilled in the art.

What is claimed is:

l. A rotor for a rotary-piston mechanism supported for rotation between spaced end walls of a housing of the mechanism, said rotor comprising:

a. a body portion having opposite end faces and a plurality of circumferentially spaced apex portions in said opposite end faces;

b. a plurality of bearing members each of which is disposed in an apex portion of the opposite end faces of the rotor;

c. each bearing member comprises:

l-a. outwardly means projecting rim means extending from the plane of the end face of the rotor and defining an enclosed shallow space; and

2-a. a layer of bearing material having selflubricating characteristics being disposed in said shallow space and projecting flush with the outer surface of said rim means.

2. The apparatus of claim 1 wherein said rim is an integral part of the rotor.

3. The apparatus of claim 1 wherein said rim means projects from the plane of the end face of the rotor a distance of about 0.1 mm.

4. The apparatus of claim 1 wherein said layer of bearing material is molybdenum.

5. The apparatus of claim 1 wherein the rotor is made of light metal alloy, the housing is gray iron and the layer of bearing material is molybdenum.

6. The apparatus of claim 1 wherein said rim is circular in shape.

a: a: a:

" i v f UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Dated November, 13. 1973 Patent No. 3. 771,904

Inventor(s) Max Ruf It is cerfified that error appears in the above-idehtified patent and that said Letters Patent are hereby corrected as shown below:

IN THE CLAIMS:

Column 4,' line 9, after the word "outwardly" delete the word -means.

'Sig n ed and sealed this 16th da of July 1971 (SEAL) Attest:

MCCOY M. GIBSON, JR. 0, MARSHALL DANN Attest aing Off ioe-r Commissioner of Patents USCQMM-DC 60376-P69 9 U. GOVERNMENT PRINTING OFFICE l9! 0-366-334,

FORM PO-105O (10 69) 

1. A rotor for a rotary-piston mechanism supported for rotation between spaced end walls of a housing of the mechanism, said rotor comprising: a. a body portion having opposite end faces and a plurality of circumferentially spaced apex portions in said opposite end faces; b. a plurality of bearing members each of which is disposed in an apex portion of the opposite end faces of the rotor; c. each bearing member comprises: 1-a. outwardly means projecting rim means extending from the plane of the end face of the rotor and defining an enclosed shallow space; and 2-a. a layer of bearing material having self-lubricating characteristics being disposed in said shallow space and projecting flush with the outer surface of said rim means.
 2. The apparatus of claim 1 wherein said rim is an integral part of the rotor.
 3. The apparatus of claim 1 wherein said rim means projects from the plane of the end face of the rotor a distance of about 0.1 mm.
 4. The apparatus of claim 1 wherein said layer of bearing material is molybdenum.
 5. The apparatus of claim 1 wherein the rotor is made of light metal alloy, the housing is gray iron and the layer of bearing material is molybdenum.
 6. The apparatus of claim 1 wherein said rim is circular in shape. 